Safety electric fuse igniter



Feb. "i, 192s. 1,658,610

N. M. oLEvlcH SAFETY ELECTRIC FUSE IGNITER Filed June 18, 1927' MJ man,

Patented Feb. 7, 1928.

. QUNTE STATES NICHOLAS MICHAEL OLEVICH, OFS'I, CLAIR, PENNSYLVANIA.

SAFETY ELECTRIC rusa IGNITER.

Application tied .Tum-18, 1927. serial No. 199,754.

This invention relates to improvements in electric fuse lighters, and relates particularly to a sate construction ot such devices which makes it possible for them to be r employed in explosive gaseous atmospheres. It has heretofore been proposed to employ the electric spark or an electrically energized heater for igniting a detonating fuse: but such .devices were not safe for employment in the presence of an atmosphere of explosive gases, since the fuse itself, or the spark for igniting it, might easily set tire to the surrounding explosive atmosphere and cause disaster. 'The present invention proposes a sate construction of such devices by which it is possible to observe the progress of combustion of the fuse, and to .retain it under safe conditions against causing ignition of gases until it ceases to. emit igniting sparks: and further the gaseous atmosphere is prevented romcontact with the heater element proper under conditions which might lead to a general explosion.

The device is simple, readily operated, safeand easily repaired in case of damage. `-On the accompanying drawings, which illustrate one torni of construction of aV device according to this invention: Figure 1 isy a` perspective iew of the exterior of such a device.

Fig. 2 is a longitudinal axial section through the device. Fig.v 3 is a side elevation of certain details of the device, substantially at right anglesto the position shown in Fig. 2. A In these drawings, the casing 10 comprises a large tube having the closing end caps 11, 12' thereon which are sealed with respect to the tube against the admission of gas except in very minute quantities. Vindows 13, 14. are provided on opposite sides of the tube 10. An inner tube 15 of closelnesh wire gauze is provided within the outer tube 10 and serves to prevent the propagation of an explosion by any combustion of gaseous atmosphere within the casing 10, in the same manner as this function is accomplished in the ordinary Davy safety lamp now employed in coal mines.

The end cap 11 has an outwardly extending hollow stem 16 having an electrical insulating bushing 17 thereon to guide the electrical conductors 18. Within the sleeve 16 is threadedly engaged the threaded metal tube 19 which is provided with a lock nut 20 to seat the member 19 'tixedly with respect to the cap 11. At its inner end the tube 19 carries the head 21 having the threaded metal projection 22 to receive the threaded end 23 of av small electric heater 24, which may be of the vcigar lighter type, and is provided with a central ret-urn contact terminal ,25 which -engaged with the metal central Vportion 26 of the head `21. VIt will be understood that by this means a circuit is completed from a. battery connecting the ends ot the conductors 18, through one of these conductors and the heater24, and back through the other conductor 18 `to the battery again.

The other end cap 12 'is provided with-.an outwardly extending guiding sleevev 27 which is supported within the hub 28 of the cap 12. It is preferred to threadedly engage the guide sleeve 27 in the hub 28 and to secure the posi-tion of these members with respect to each other by the lock nut 29. The end of the guide sleeve 27 projecting within the casing 10 carries a valve head 30 threaded thereto, this valve head having `a pivot 31 thereon extending substantially in a plane at right angles tothe axis ot' the guide tube 27. Mounted on this pivot is the valve plate 32 which is rockable about the pivot between the positionsY shown in full lines and Vin dotted lines in F ig. 3. The valve plate 32 is provided with the ears 33 to receive the ends or the coil springs 3d, whose other ends are engaged in the ears "35 of a bushing 36 which .is likewise threadedly engagedv along the length of the guide sleeve 27.

The operation ot' the devicelis very simple. The current from a battery, suchas the electric light battery tor .the miners lamp, is connected to the conductors 18, with the intercalation ot a switch, it such be desired. The heater 24 attains an incandescent temperature, which may be observed through the windows 13, 14 from the exterior of the casing 10. The operator now knows that the device is ready to ignite fuses. The length ot fuse, such'as F in the drawings, is then pushed through the guide portion 28 from the exterior and passes freely down within the guide tube 27 and closes the same, except for a very small passage around the side walls which is insuiiicient for the propagation of an explosion, in accordance with the well known operation of the Davy safety lamp. As the end ot' the fuse reaches the valve plate 32, the latter is moved from posiaon 'saowiiiiaiuii -iines to that shown in' dotted linesiiiFig.' 3, and the end of `the fuse passes further andinto contactrvvitli the incandescentilie'ater 24, and inrpartioug-f;

lar into contact with ythe hot' wires24 thereof, as vshown in Fig.'y A'sli'ght pressure-on j the fuse F is'all that has 'beeiirequired'or this operation, and the use'is held in thisl positionuntil the lire-transmitting core 'be- ,comesignited.V As 'soon'as thisignition oc# curs, the fuse delivers showerot sparks, which'areeasily visible Vfrom the 'exterior' of v the casingy l0 through the wiiidows'13, 14:.l

The yfuse may be slightly withdrawn. if so des sired, and the course ot this sho'wer'observed y until the fizz'ing ceases.` It is'obvious that if there are no sparks, it is no longer dangerous tok exposetlie end of the fuse to the art--V inosphere surrounding, keven though the fuse lias'been liglited.` The device is therefore-V pulled of'tlie endv of' the fusefduring which y the valve plate regains its position and closes the apert'urethiough which the fuse enteredv 1 the interior of the casing l0.V The device maytlien be employed to ignite another length otfuse, etc. without any danger arising of exploding a dangerous gas eous atmosphere. .It will be particularly noted that the heater 24 may be kept at an .incandescent temperature Without anyvdanger arising.I "The gaseous atmosphere enters and leaves the casing l0 freely through the Windows 13, A14: as in the usual Davy safety lamp, and the mesh ganze cylinder'l prevents any possibilityl of the propagationof an explosion to the eXteriorso long [as the valve vplate 32 is closed. This plate, how# p The ullloourse ofxtheig? nitionlis observed from thevv exterior throughf ment may be Veasily unscrewed by the threads 23, and a new one substituted at a very 10W expense. ments of .the system.;

It is obvious that theinvention'isiiot limi ji ited tothe particular form of illustration einevr .y

ployed, but'tliat it may be inodied in many ways within claims.

A I claim;

y "1i A'satety fuselighter comprising acasf' ing, an ignite'rfwithinj'said casing, and 'a The same' is true of the otlrer ele-v f the scope A of the` appended y guide conduit' fory tlie fuse passing .throughi l the wall ot' said casing and'aliiied witli's'aid-'l igniter, the passage through said'conduitfrv being substantially closed by the" fuse, ysaid; L

casing having explosion-'proof z 'wiifidows therein whereby the igi'iitionaridjcourser of coinbustion'may be observed so that the operator inay'detei'inine the time. at which the Y fuse vmay safely lighter.

'be withdrawn fromY @he 2. safety i'use lighter coinpi'ising'a oas#v i ing, an 'igniter within said casing, a guideA tube for the fuse passingftlirough the-wall of f said' casing and alned with said ignite'ij, and

a valve. to close saidtube. v n

3. A safety luse lighter comprising'a casing, an electrically lieatable igniter within said casing, a guideconduit ytor'v theffuse i passiiigthrougli the wall of said casiiigandl alined with said igniter; the passage'tlirough said conduit being substantially Yclosed 'by the fuse, and an automatically closing valve at the inner end of saidcondui't," said 'valvev being'opened bythetuse inpassingto thef position :torignition and closingautomatiy cally prior {tjo tliewitlidrawalvoftheffuse'I from lsaid conduit,vsaidrcasing havingl apen- `tures therein, andY safetyA wireY gauze',Closingj said apertures against the propagation'iof an explosion therethrough, said'A apertures;v .i

permitting thef'observing of the courseo `igi i, nition and combustion of fuse, andsaid .Valvef -kf Y preventing the propagatioiiof anreXplosioii from said igniterthrough'saidltube."

In testimony whereof', I ax my s'ig'na'tiire;

YNlCHOLAS iaixgiiiiiajp. OLEVICH, 

